Limitations on measuring a transverse profile of ultradense electron beams with scintillators

As high-brightness electron beams become denser and reach sub-100 /spl mu/m sizes, a resolution of the transverse profile diagnostics become an important issue. The applicability of traditional scintillators as the diagnostics for most generic transverse properties of small dense beams is questionable. Recently, a YAG:Ce single crystal was used successfully, but studies indicated the presence of saturation effects. At BNL-ATF (Accelerator Test Facility) we have generated ultra-small beams, and continued an experimental work to further illuminate the nature of YAG:Ce saturation. We have also evaluated alternative diagnostics, such as LuAG:Ce. Imaging properties of various diagnostics were studied, including measurements of emission spectra.